The present invention relates to a pressure reducing valve that is particularly useful, for example, in a high-rise building application in a fixed fire protection system.
In high-rise buildings, the riser pipe of the fire protection system, which is typically located in a stairwell of the building, operates with a relatively high pressure in order to have a sufficient operating pressure at the highest elevation of the building. When firefighters need to access the water in these fire protection systems, for example, in the riser pipe, the pressure in the system typically exceeds the maximum pressure ratings for the fire protection components. In addition, at the lower elevations, the pressure may exceed pressure ratings for the sprinkler piping components.
In order to reduce the pressure, fire protection systems have incorporated pressure reducing valves, which reduce the pressure of the valve at intermediate elevations along the riser so that the water pressure is reduced to acceptable levels for firefighting equipment for the sprinkler piping. Prior art valves, which typically provide a handle to open or close the valve, are often hard to operate because the force exerted on the handle must exceed the spring force of a compression spring, which is used to automatically reduce the water pressure. In high-rise building applications, the compression force of these springs can be significant, for example, on the order of 1,500 pounds. In some jurisdictions, a separate upstream valve may be required because the valves are so hard to use.
Consequently, there is a need for a pressure reducing valve that is easier to operate to provide access to lower pressure water in a high-rise fire protection system, without comprising the function of the pressure reducing valve.